Contact members used for electronic components described above may be made of a base material of copper or a copper alloy such as phosphor bronze or brass and a gold plating applied thereon. Gold plating prevents an oxide film, and has a good contact resistance value stability and a good corrosion resistance.
As described in Patent Document 1 below, the applicant has proposed providing an appropriate plating layer between a conductive base material and a main plating layer formed on the conductive base material to prevent corrosion and to improve connection reliability of a contact member, and, according to this proposal, a good result is obtained in a corrosion resistance test using a three-gas mixture flow (H2S, SO2, NO2).